Methods and systems for forming concentrated consumable extracts

ABSTRACT

Typical known methods for producing large quantities of concentrated extracts from solid raw materials such as ground, roasted coffee are not ideally suited to producing high quality coffee extracts that are rich in flavor and fragrance, and which maintain the varietal characteristics of the roasted coffee from which they are produced. The current invention provides filtration methods e.g. reverse osmosis or nanofiltration for producing such high quality concentrated extracts from more dilute extracts via solvent removal. The invention provides methods that have sufficient flexibility and scalability to be used for a wide variety of applications, including for producing industrial—scale quantities of extracts for the food and beverage industry. The invention provides methods and apparatus that can produce highly concentrated, “gourmet quality” extracts for use as flavoring agents, beverage concentrates, and fragrances. The solvent—reduced, concentrated extracts produced according to the inventive solvent removal methods can be advantageously used for applications where high quality coffee extracts, with a high concentration of soluble coffee solids, for example of at least 6 wt. %-40 wt. %, and a high level of retention of varietal flavor and fragrance characteristics are desired.

RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. §371 ofInternational Application No. PCT/US00/29651 filed 27 Oct. 2000, whichwas published under PCT Article 21(2) in English. This Internationalapplication claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Application Ser. No. 60/161,981, filed Oct. 28, 1999.

FIELD OF THE INVENTION

The present invention relates to methods and systems for producing aconsumable aqueous extract from a solid raw material, and, morespecifically, to methods and systems for concentrating such consumableextracts through the use of filtration. Specific embodiments of theinvention involve methods for forming concentrated aqueous extracts ofroasted coffee useful in food, fragrance, and beverage products.

BACKGROUND OF THE INVENTION

A variety of solid raw materials are commonly extracted with aqueoussolvents, such as hot water, to form consumable aqueous extracts for usein foods, fragrances, or beverages. Common materials include roastedground coffee, tea, and cocoa just to name a few. Typical andrepresentative of currently employed methods and systems for performingsuch extractions are those used for brewing and extracting roastedcoffee. Generally the prior art systems fall into two broad categories:small-scale home or commercial brewing equipment for producingbeverages; and large-scale industrial extractors for producingconcentrated extracts for use as flavorings or as raw materials for theproduction of instant coffee products. When used for the production ofinstant coffee products, the aqueous solvent is typically removed fromthe dissolved coffee solids by processes such as freeze drying or spraydrying.

Typical prior art large-scale coffee extractors and associatedextraction methods, especially when used to produce coffee extracts forthe subsequent production of instant coffee, are designed toexhaustively extract a given quantity of ground roasted coffee andhydrolyze the cellulose of the roasted coffee. This is done for economicreasons: the more soluble coffee solids extracted from a given quantityof roasted coffee raw material, the greater the quantity of finalinstant coffee product derived upon removal of the water by drying. Tothis end, typical prior art large-scale coffee extractors are designedfor the exhaustive extraction and hydrolysis of typically low-gradeground coffee and not for production of a high quality, flavorful,fragrant extract or for the production of various grades of extract froma given quantity of ground, roasted coffee. Many typical prior artextractor systems of this type employ one or more columns having fixedbeds of ground roasted coffee. Representative of such a system is theone described in U.S. Pat. No. 3,830,940 to Sivetz. While such systemsand methods are useful for exhaustive extraction with hydrolysis, theyare not ideally suited for producing high quality coffee extracts withdesirable sweetness and flavor characteristics or for production ofvarious grades of extracts from a given choice of ground, roastedcoffee. The relatively long extraction times (for example greater than 1hour), high water temperatures, and levels of dilution used in certainprior art extraction processes can result in extracts having poor flavoror fragrance characteristics, which are often passed on to the driedinstant coffee products produced from such extracts. Furthermore, theprocess of de-watering the extracts by typical prior art methods, suchas spray drying or freeze drying, in forming the instant coffee productscan result in the loss or degradation of desirable varietal flavor andfragrance components of the ground, roasted coffee. Many of theconcentrated coffee extracts commonly employed as flavor components inthe food industry (e.g. as flavorings for coffee ice cream, iced coffeebeverages, and coffee syrups) are produced by reconstituting such poorquality instant coffee products with water or other materials.

It is understood that sweeter and more flavorful coffee extract can beproduced near the beginning of an extraction cycle, when the freshground coffee has been in contact for a relatively short period of timewith only a relatively small quantity of water, than can be producedlater in the extraction process after the coffee has been exposed toadditional quantities of water and more exhaustive extraction. Attemptshave been made to improve upon the quality and flavor of coffee extractsand instant coffee products produced by large scale extractionprocesses. One such method described in U.S. Pat. No. 4,534,985 to Gasau('985) discloses an industrial scale continuous extraction process andapparatus for the extraction of coffee or tea. The apparatus involves acomplex system using a number of extractant beds and extraction zones,where the beds are movable between zones by rotation of the apparatus.The process reduces the total time of the extraction process whencompared to more conventional prior art extraction methods. The '985patent also discloses the use of compressed air or an inert gas in a“recovery station” of the apparatus to maximize recovery of the residualliquid present in the spent grounds after extraction.

Various smaller scale brewing/extraction methods for home or commercialuse are known in the prior art for producing beverages from solid rawmaterials such as coffee, tea and cocoa. Common methods include steepingor infusion in a static volume of hot water (i.e. steeping a tea bag ina cup of hot water), steam-driven percolation, and extraction via acontinuous flow of hot water under the force of gravity through a bed ofsolid extractable material, typically coffee. The latter methoddescribed is the one typically employed in home “drip method” coffeemakers. All of these methods typically produce a relatively dilutebeverage-strength extract (typically, 1 lb of ground, roasted coffeewill yield about 320 oz. of beverage-strength extract). In addition,because of the continuous addition of water used to drive the flow ofextract through the bed, the beverages produced can contain flavorand/or fragrance undesirable quantities of certain bitter components,which may be undesirable for certain applications. Also, because theseprior art methods brew in the presence of oxygen, the flavor andfragrance of the resulting extract can be degraded by undesirableoxidation.

An improvement to most of the above described methods for applicationswhere it is desired to produce a more concentrated coffee beveragehaving a sweeter flavor and fragrance, is the espresso method of coffeeextraction. The espresso method of extraction typically employs asmall-scale home or commercial brewing apparatus utilizing a lessexhaustive extraction method to produce a relatively sweet, moreconcentrated beverage. Typically, a higher ratio of ground coffee to hotwater is employed, for example about 1 lb. of ground roasted coffee maytypically yield about 64-128 oz of coffee beverage. In order to allowsufficient contact time between water and the ground coffee, the methodtypically utilizes a finely ground coffee (e.g. 14 gram weight) with hotwater being forced through the bed of grounds contained in the brewchamber by additional pressurized hot water. Most typical currentlyemployed espresso type extraction devices are capable of producing onlyrelatively small quantities of extract during each extraction cycle. Inaddition the quality of the beverage can be very dependant on the grindand packing of the coffee, which dictates the back pressure developed bythe flowing water during the extraction, and the extraction time for agiven total volume of beverage. A lack of control over these variablescan lead to a poor or inconsistent quality of extract. Also, since hotwater is typically used to force extract from the bed of ground coffeeduring the entire extraction process, a level of extraction that isundesirable for certain applications may still occur, yielding anextract which may be too dilute for certain applications, and may not beideally suited for use as a food or flavor additive.

A variety of small-scale espresso style coffee brewers have beendescribed which attempt to improve upon the performance of conventionalespresso brewers. U.S. Pat. No. 5,127,318 to Selby ('318) and U.S. Pat.No. 5,473,973 to Cortese ('973) both disclose an apparatus and processfor extracting espresso type coffee in which the pressure within theextraction region is regulated by a biased valving arrangement on theoutlet line downstream of the coffee bed. The valves are designed toremain closed during the initial pressurization of the extractionchamber by hot water until a preset pressure is reached that canovercome the bias of the regulating valve. When such pressure isreached, the valve opens for flow and maintains a relatively constantpressure in the extraction chamber during the remainder of theextraction process relatively independent of the grind or packing of thecoffee. In the disclosed systems, the pressure constantly rises until apredetermined pressure is reached, at which point, flow immediatelycommences.

U.S. Pat. No. 5,267,506 to Cai ('506) discloses an apparatus forautomatically brewing espresso coffee and includes one embodiment wherepressurized steam generated by a heating unit is passed through thecoffee grounds to purge liquid so that the grounds will not drip whenthe brew chamber is removed.

U.S. Pat. No. 5,337,652 to Fischer et al. ('652) discloses an espressomachine and method utilizing a biased pressure relief valve down streamof the brewing chamber similar to U.S. Pat. No. 5,127,318 ('318) andU.S. Pat. No. 5,473,973 ('973) described above. The biased valveprevents flow from leaving the discharge line until the pressure withinthe chamber rises to a fixed predetermined level; immediatelythereafter, the valve opens and maintains a relatively constant pressurewithin the brew chamber during the remainder of the extraction. The '652system also includes an air pump with an outlet line in fluidcommunication with the water heating chamber. The air pump is used atthe end of the brewing cycle to pump air through the coffee grounds inorder to dry the coffee and produce a foamy head. The air from the pumpis directed to the brewing chamber from the hot water compartment via arelatively complex automated valving/switching mechanism on a flowcontrol manifold located within the water heating chamber. The airsupplied to the brewing chamber in the '652 system passes through thewater heating chamber before entering the brewing chamber thus addingheat and moisture to the gas. While some of the above cited systems andmethods for producing consumable extracts from solid raw materialsrepresent, in some cases, useful contributions to the art of producingconsumable extracts, there exists a need for improved methods andsystems for producing variable quantities, including large volumes, ofconsumable extracts, including highly concentrated extracts, from solidraw materials, the extracts having a desirable combination of sweetness,flavor, and fragrance characteristics.

SUMMARY OF THE INVENTION

Accordingly, the present invention, in some embodiments, can provideimproved methods and apparatuses able to controllably produce highlyconcentrated or less highly concentrated consumable extracts havingexcellent and desirable sweetness, flavor, and fragrance qualities fromsolid raw materials. In other embodiments, methods and apparatuses areprovided that utilize filtration methods, such as reverse osmosis and/ornanofiltration, to remove excess solvent from consumable extracts toproduce more concentrated extracts with minimal loss of desirable flavorand fragrance characteristics.

In one aspect, a method is described for increasing the concentration ofa consumable material in a consumable extract. In one embodiment, themethod comprises supplying the extract to the retentate side of a filterand passing at least a portion of the solvent component of the extractthrough a filtration medium to form a permeate on the permeate side ofthe filter while retaining at least a portion of the consumable materialon the retentate side of the filter, thereby forming a solvent-reducedconsumable extract. This solvent-reduced consumable extract is moreconcentrated in the consumable material and is collected from theretentate side of the filter.

In another embodiment, a method for producing a blended coffee extractis disclosed. The method comprises extracting a quantity of roastedcoffee with a quantity of aqueous solvent to form a first-pass coffeeextract having a concentration of dissolved coffee solids of a firstvalue. The method further involves extracting the same quantity ofroasted coffee previously extracted in the above step with an additionalquantity of aqueous solvent to form a second-pass coffee extract havinga concentration of dissolved coffee solids therein of a second valuethat is less than the first value. The method further comprisesincreasing the concentration of dissolved coffee solids in thesecond-pass coffee extract by removing a quantity of aqueous solventfrom the second-pass extract. The method further includes mixing aquantity of the first-pass extract with a quantity of the second-passextract, concentrated in the above step, to form a blended extract.

In another aspect, an aqueous coffee extract is disclosed. The extractis obtained by extraction of a quantity of roasted coffee that includesat least one chosen variety of roasted coffee. The extract contains atleast about 15% wt. dissolved coffee solids and retains an effectiveamount of the varietal flavor and fragrance components characterizingthe at least one chosen variety of roasted coffee from other varietiesof roasted coffee.

Other advantages, novel features, and objects of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings, which areschematic and which are not intended to be drawn to scale. In theFigures, each identical or similar component that is illustrated invarious Figures is represented by a single numeral. For purposes ofclarity, not every component is labeled in every Figure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an apparatus for forming aconsumable extract from a solid raw material according to one embodimentof the invention;

FIG. 2 is a schematic illustration of the apparatus shown in FIG. 1 asviewed from the top;

FIG. 3 shows a cross-section of the apparatus in FIG. 1 as viewed fromthe top showing one embodiment of a filter element comprising a porousscreen;

FIG. 4 is a cross-section of the apparatus of FIG. 1 viewed from theside showing the enclosed internal volume and internal components of thevessel;

FIG. 5 is a schematic illustration of a portion of a filter system forconcentrating a consumable extract, according to some embodiments of theinvention; and

FIG. 6 is a schematic process flow diagram of a filtration-based extractconcentration system, according to one embodiment of the invention

FIG. 7 is a schematic process flow diagram of a filtration-based extractconcentration system, according to another embodiment of the invention

FIG. 8 is a schematic process flow diagram of a filtration-based extractconcentration system, according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention involves methods for forming consumable extractscontaining a consumable material from a variety of solid raw materials,which extracts can be of superior quality with regard to flavor andfragrance compared to similar extracts produced according to typicalprior art extraction methods. Some embodiments of the invention alsoinvolve novel methods for removing excess solvent from consumableextracts to form a more concentrated extract, without substantiallydegrading the flavor and fragrance characteristics of the extract. Theterm “consumable extract” as used herein, refers to a solutioncontaining a dissolved or suspended consumable material in a consumablesolvent. A “consumable solvent” refers to an essentially non-toxic,ingestible liquid that has the ability to dissolve or suspend a non-zeroquantity of the consumable material. “Consumable material” as usedherein, refers to an extractable component of a solid raw material thatis extracted by, and can be dissolved or suspended in, the consumablesolvent. A “solid raw material” as used herein, refers to a solidmaterial including at least one solid component that is insoluble in theconsumable solvent and at least one other component that is a consumablematerial. Preferred consumable solvents for use in the invention areaqueous solvents. An “aqueous solvent” according to the inventioncomprises water, and may additionally include other components that aresoluble or miscible in the water, which components may be useful ordesired for particular applications. When an aqueous solvent is employedin the invention, the consumable extracts produced will be aqueousextracts.

The solid raw materials that may be advantageously employed according tothe invention can include a variety of organic solids from whichconsumable materials can be extracted, for example, tea leaves, cocoa,fruit, vanilla beans, and roasted coffee. While it should be understoodthat the methods and apparatus described herein in accordance with theinvention can potentially be used for any suitable solid raw material,including but not limited to those listed above, to exemplify the methodfor the purpose of the detailed description, specific reference will bemade to roasted coffee.

Unlike typical prior art methods and apparatus for producing aqueousextracts from roasted coffee (i.e. coffee extracts), the currentinvention enables the production of relatively concentrated coffeeextracts that exhibit a high level of sweetness and flavor quality andretain the varietal characteristics specific to the particular varietyof coffee being extracted. Unlike typical prior art methods forproducing concentrated coffee extracts, for example for use in producinginstant coffee, the inventive methods, in some embodiments, avoidexhaustive extraction of the roasted coffee with high water temperaturesthat can lead to hydrolysis (typically above the boiling point of waterat atmospheric pressure), which can lead to loss of fragrance andextraction of an undesirable quantity of bitter components and acidsthat can adversely affect the flavor and fragrance of the extract. Insome embodiments, more than one different grade of extract may beproduced from a given quantity of ground roasted coffee, with eachextract produced at a different level of exhaustion of the coffee. Asdescribed in more detail below, these extracts can be concentrated andcombined in a variety of ways to yield combined extracts having avariety of flavor/fragrance characteristics.

Coffee's sweetest flavors are typically produced during the first partof any brewing (extraction) cycle for typical prior art methods. Richflavors, sugars, and aroma are extracted first. Oils, acids, and morebitter flavor components brew out in the later phase of brewing whenmore extensive extraction has occurred. This, for example, is why somepercolated coffee beverage and coffee extract produced by exhaustiveextraction is often bitter in flavor, has weak aroma, and has oils onthe surface.

For applications where coffee extracts having superior fragrance andflavor are typically not considered crucial, for example for productionof instant coffee products, exhaustive extraction with hydrolysis hasbeen utilized in an attempt to maximize the total yield of consumablematerial (i.e. soluble coffee solids) that can be obtained from a givenquantity of solid raw material (i.e. roasted coffee). However, becauseof harsh extraction conditions and solvent removal conditions oftenemployed in these prior art processes, when reconstituted with water oranother solvent to form a coffee beverage or coffee extract for use as afood, flavoring, or fragrance component, such prior art productstypically do not provide the flavor and/or fragrance characteristicsdemanded by consumers who appreciate superior quality coffee.Specifically, these prior art exhaustive extraction methods typicallyproduce coffee extracts that do not retain the desirable varietal flavorand fragrance components that can distinguish extracts produced fromcoffee grown in one particular region or country or blends of two ormore such coffees over other, different varieties. The extracts producedaccording to the present invention can provide flavor and fragranceattributes that enable them to be utilized in “specialty” coffeeapplications, and for those embodiments designed for such specialtycoffee applications, retain an effective amount of the varietal flavorand fragrance components characterizing the particular variety ofroasted coffee from which the extract was produced. The varietal flavorand fragrance components, advantageously retained in coffee extractsproduced according to these embodiments of the invention, are relativelyvolatile extractable chemical compounds, or combinations of chemicalcompounds, present in the roasted coffee. Different coffee varieties(e.g. Costa Rican Tarrazu vs. Sumatran Mandheling), or defined mixturesor blends of such varieties, will typically possess different relativeamounts of and/or types of these varietal flavor and fragrancecomponents that distinguishes the flavors and fragrances of thedifferent brewed coffees. The presence of these varietal flavor andfragrance components is conventionally determined by cupping (taste andsmell testing) by those skilled in the art. Unlike typical prior artmethods of producing relatively concentrated coffee extracts, which donot contain effective amounts of these varietal components, the presentinvention can provide relatively concentrated coffee extracts that doretain effective amounts.

“Relatively concentrated coffee extract” as used herein, refers to acoffee extract that is more concentrated than coffee beverage-strengthextract (typically about 1-4% wt. dissolved coffee solids) and containsat least about 6% wt. dissolved coffee solids. An “effective amount” asused herein in reference to the amount of varietal components retainedin a coffee extract refers to a concentration of such components in theextract sufficient to be detected, in the concentrated extract itself orin a coffee beverage obtained by diluting the extract to beveragestrength with additional water, by taste and/or smell by one of ordinaryskill in the art of cupping (taste-testing) coffee. “Detected” as usedabove refers to the ability of such a taste tester to distinguish, dueto the presence of the varietal components, extracts produced by thesame method but from different varieties of roasted coffee.Alternatively, the presence of an effective amount of varietalcomponents can be determined and defined by performing standard chemicalanalysis on the coffee extracts. Such analysis can be performed by avariety of methods apparent to one skilled in the art, for example, gaschromatography, liquid chromatography, mass spectrometry, etc. An“effective amount” of varietal components as measured by such methodscan be defined by comparing the analysis of a beverage-strength extractproduced by a typical prior art beverage brewing method, such as thedrip method or espresso method, both discussed in more detail herein,with a concentrated extract that has been diluted with additional waterto have the same total dissolved solids as the beverage-strength extractto which it is being compared. A diluted concentrated extract soanalyzed with an “effective amount” of varietal components, will containabout the same or greater concentration of such components as thebeverage-strength extract produced by the typical prior art beveragebrewing method.

In addition, because the inventive methods provide flexibility toproduce coffee extracts having a wide range of solubles concentration,including highly concentrated extracts, many of the extracts producedaccording to the invention can, in some embodiments, be used directlyfor applications where highly concentrated coffee extracts aredesirable, without the need for additional concentration by solventremoval. For example, concentrated coffee extracts produced according tosome embodiments of the invention can be used for producing coffeesyrups, coffee ice creams, iced coffee beverages, coffee perfume, etc.,all of which can display excellent flavor, sweetness, and/or fragranceand maintain the varietal characteristics of the coffee from which theproducts were produced. For other embodiments where it may be desirableto even further concentrate the extracts produced by extraction of theground, roasted coffee, the invention provides novel filtration-basedmethods, for example reverse osmosis methods, for removing excesssolvent (e.g. de-watering) from the extract, preferably without undulydegrading the flavor and fragrance qualities of the dilute extract. Suchsolvent removal methods can be especially useful for formingconcentrated extracts in embodiments involving exhaustive or relativelyhigh levels of extraction of the ground, roasted coffee with relativelylarge quantities of extraction solvent.

The current invention also provides methods and apparatus that areflexible enough to allow for production of a wide variety of extractshaving different concentrations and degrees of extraction to suit avariety of purposes and applications. The inventive methods andapparatus are also easily scalable to provide a means for producing anydesired quantity of extract. Small-scale versions of the apparatus,according to the invention, could be used for home or retail/commercialuse, while larger scale apparatus, more specifically described herein,may be used for industrial production of coffee extracts.

The current methods for forming extracts and for de-watering extracts,according to the invention, allow the level of extraction, andconcentration of coffee extract to be more precisely controlled thanwith typical prior art devices and methods. For example, typicaldrip-style coffee brewers, commonly employed for home and commercialuse, typically produce about 2.5 gallons of coffee beverage per 1 lb. ofground roasted coffee, yielding a typical dissolved solids concentrationof about 1-1.5% wt. Another popular method of producing coffee beverageis the “espresso method,” which typically involves forcing hot waterthrough finely ground, roasted coffee under pressure (typically about120-140 psig depending on the fineness of the grind and the water flowrate) over a short period of time to create an “espresso beverage.” Suchmethods typically create about 1 gallon of coffee beverage from about 1lb. of coffee and produce a beverage containing up to about 4% wt.dissolved coffee solids. In general, the “espresso method” typicallyproduces a sweeter, more concentrated beverage than the drip methodbecause it utilizes a greater ratio of coffee to water, while alsoreducing the level of extraction of the raw material (ground coffee).Apparatus for producing coffee beverage according to the espresso methodis typically limited to small scale devices having a maximum capacity ofabout 14 grams of dry, ground roasted coffee. In contrast, the presentinvention provides, in certain embodiments, methods and apparatus forproducing coffee extracts from large quantities, in some embodiments300-1300 lb., of roasted coffee. The invention also allows for a varietyof coffee extracts having a variety of flavor/fragrance characteristicsand/or concentrations to be produced according to the needs of the userby allowing the user to easily adjust the ratio of extract produced toroasted coffee employed according to need. For example, the extractsproduced according to the invention can range from those of drip coffeestrength (1 lb. dry coffee per 2.5 gallons of extract) or less, tohighly concentrated extracts, for example using 2.5 lb., 5 lb, 7 lb., 10lb., 15 lb., 20 lb., 25 lb., 30 lb., or 40 lb. of dry coffee or evenmore, per 1 gallon of extract produced, yielding concentrations ofdissolved coffee solids that can be in excess of 10% wt., 15% wt., 20%wt., 25% wt., 30% wt., or 40% wt. The flavor and fragrance quality ofthe extracts produced according to the invention varies according to thedegree of dilution and extraction during the extraction process, withextracts produced at lower levels of extraction of the roasted coffeetypically having the greatest sweetness, and extracts produced at higherlevels of extraction and greater solvent dilution, which extracts cansubsequently be concentrated by filtration/reverse osmosis as describedin more detail below, having more bitter and acidic flavor components.As described in more detail below, for certain applications, extractsproduced at relatively low levels of extraction can be selectivelycombined with extracts produced at higher levels of extraction toproduce combined extracts having a desired level of balance of sweetnessand flavor/fragrance qualities. Such extracts can be selectivelyformulated to yield a flavor/fragrance balance for particularapplications; for example, in one preferred embodiment, a quantity ofhigh-sweetness extract produced at a low level of extraction can becombined with an extract produced at a higher level of extraction, andsubsequently de-watered to a solubles concentration level similar tothat of the high-sweetness extract, to produce a concentrated extractwhich yields a well-balanced, flavorful coffee beverage uponreconstitution of the extract with sufficient water to yield beveragestrength coffee.

The basic features of the inventive methods for producing consumableextracts from solid raw materials will now be explained in reference tothe formation of coffee extracts. Following the basic description, amore detailed description of each step will be given with reference toone illustrative embodiment of an extraction apparatus shown in FIGS.1-4.

The inventive extraction methods, in some embodiments, are similar, insome respects, to the “espresso method” of coffee extraction previouslydescribed. The inventive method utilizes an extraction vessel, chamber,or enclosure having an enclosed internal volume sufficient to contain adesired quantity of solid raw material, for example roasted coffee. Awide variety of extraction vessel sizes and configurations canpotentially be employed for various applications as apparent to theskilled artisan. The vessel should be sealable, so that the internalvolume can be pressurized to a desired level without undesirableleakage, and have at least one inlet line and at least one outlet linefor fluid flow therethrough to enable a continuous flow of solventthrough the solid raw material (e.g. coffee) contained within theinternal volume of the vessel. The vessel should also have means forfilling the internal volume with roasted coffee; for example, the vesselcan comprise two or more separable parts that may be separated to exposethe internal volume for filling, and/or may have one or more linesthrough a wall of the vessel and in communication with the internalvolume through which roasted coffee may be inserted into the internalvolume. The inlet and outlet lines for fluid flow are preferably locatedon the vessel on opposite sides of the internal volume containing thecoffee so that essentially all of the fluid flow entering the vesselthrough the inlet line and leaving the vessel through the outlet linepasses through essentially the entire quantity of coffee as it flowsthrough the vessel. A preferred configuration of the vessel has one ormore inlet lines located at or near a top surface of the vessel and oneor more extract outlet lines located at or near a bottom surface of thevessel, thus allowing, in preferred embodiments, a flow of aqueoussolvent through the coffee to proceed from above the level of the coffeein the internal volume and through the quantity of coffee in theinternal volume in the direction of gravity. Such flow through thecoffee in the direction of gravity acts to compress the coffee duringflow-through extraction and improve contact between the solvent and thecoffee, thus improving the extraction process performance as compared toa solvent flow against the direction of gravity or perpendicular to thedirection of gravity.

One embodiment of a method for forming a coffee extract according to theinvention involves first at least partially, and preferably essentiallyentirely, filling the internal volume of the vessel with roasted coffee.With the certain lines closed and at least one valve on a line in fluidcommunication with the internal volume of the vessel open, the vessel isat least partially filled with an aqueous solvent. The aqueous solventcan be filled, in some embodiments, through inlet line(s) on the top ofthe vessel, or, more preferably, at least a portion of the initialfilling of the vessel with aqueous solvent can be performed by flowingthe aqueous solvent into the vessel through one or more lines positionednear the bottom of the vessel, for example below the filter screen used,in other steps of the extraction process as extract outlet lines orwashout lines. This latter filling process can help reduce potentialclogging of the filter screen (see FIG. 3 and discussion below) withfines of the roasted coffee by back-flushing the screen during initialfilling with aqueous solvent.

Preferably, enough aqueous solvent is added to fill the void volume ofthe quantity of roasted coffee in the vessel and completely cover andwet the roasted coffee. The outlet lines are preferably closed throughmeans of at least one controllable valve. A “controllable valve” as usedherein refers to a valve that may be manually or automatically operated,for example by hand turning or computer control and actuation, asdesired by an operator to open, close, and/or partially open or closethe valve at any desired time and under a variety of desired operatingconditions. Such valves may be gate valves, globe valves, ball valves,needle valves, etc. as apparent to the skilled artisan and aredistinguished from valves which open and close at one preset conditionwithout operator control, such as, for example, a biased pressure reliefvalve. In preferred embodiments, the temperature of the aqueous solventin contact with the coffee is above ambient temperature, mostpreferably, it is between 190 and 212 degrees Fahrenheit.

Preferred embodiments of the extraction method, subsequent to thefilling steps outlined above, next subject the roasted coffee to a novel“pressure-treat” step, which facilitates thorough wetting of the coffeeand the elimination of air pockets or channels, as well as penetrationof the aqueous solvent into the coffee particles themselves to increasethe efficiency of extraction. The pressure-treat step is performed byincreasing the static pressure in the vessel containing the coffee andaqueous solvent to a predetermined and controllable pressure aboveatmospheric pressure while maintaining the outlet valves in a closedconfiguration so as to prevent any flow of extract from the vessel. Thevessel can be pressurized by addition of additional pressurized aqueoussolvent, or alternatively by addition of a pressurized gas to the vesselfrom an external source of pressurized gas through an inlet line to thevessel. The pressure is maintained for a desired period of time beforeflow of extract is established. The optimal level of pressure for use inthis “pressure-treat” step depends on whether the roasted coffee is inthe form of whole beans or ground, the fineness of the grind (for groundcoffee), the type of coffee, the degree of roasting, etc., and should bedetermined by the operator, using routine experimentation and/oroptimization, for a given set of conditions to produce an extract withdesired characteristics. In general, the coarser the grind of coffee,the higher the pressure should be to yield maximum benefit from thepressure-treatment. It has been found that for many types of groundcoffee (e.g. roasted coffee ground using a Bunn coffee grinder (HVG,Bunn-o-matic, Springfield, Ill., on a setting of 4.0, or roasted coffeeground to a similar average coarseness using a roller mill grinder) thepressure during the pressure-treat step is preferably at least about40-50 psig, in some embodiments at least about 100 psig, and, in certainpreferred embodiments, between about 120 and 132 psig. For embodimentswhere coarser ground coffee or whole bean coffee is used, the pressureis preferably higher than this range, for example 150-1000 psig or more.The pressure is maintained under non-flow conditions for a predeterminedand controllable period of time before the onset of flow. The time oftreatment can vary from several seconds to several minutes, with atypical static pressure treatment time being about 10-30 min.

Upon completion of the static pressure-treat step, an outlet valve is atleast partially opened to establish flow of extract from the vessel,and, for some embodiments, additional aqueous solvent is simultaneouslyfed to the vessel through an inlet line. The valve on the outlet linecan be controlled to maintain a desired level of pressure within thevessel during the flow-through extraction. Thus, the ability of theoperator to select and control the pressure in the vessel via control ofan outlet valve allows the pressure during extraction and to be adjustedand controlled within the vessel independent of the fineness of thegrind of coffee or the inlet solvent and/or gas flow rate. Forembodiments where a very concentrated extract is desired, very little orno additional aqueous solvent is supplied during flow of the extractfrom the vessel. For other embodiments, a measured, desired quantity ofadditional aqueous solvent is supplied to yield a desired level ofextraction and final extract concentration.

After a desired quantity of additional solvent has been supplied, theflow of solvent is discontinued and extract is collected through theoutlet line, typically until the vessel is equilibrated with atmosphericpressure. At this point, in preferred embodiments of the method,residual extract present within the void volume of the ground coffee isremoved and recovered by supplying the vessel with a flow of fluid thatis a gas (at standard temperature and pressure) through an inlet line tothe vessel, which is in direct fluid communication with the enclosedinternal volume, from a source of compressed gas external to the vessel.The gas flow to the vessel displaces the extract from the wet coffee,which extract is collected from the outlet line and added to the extractcollected during the previous step. Purging the wet coffee with a gasallows the concentrated extract present within the void volume, definedby interstices between and within the wet coffee particles, to berecovered instead of wasted as in typical espresso-type coffeeextractors. It also allows for a given volume of extract to be collectedwith less dilution and a lower degree of extraction when compared toprior art methods where all of the extract collected is forced from thecoffee with additional solvent. The gas used to purge the coffee, inpreferred embodiments, does not act as a solvent and, therefore, doesnot further extract or dilute the coffee extract collected. Preferredgases for use in the invention are relatively inert with respect to thesolvent, extract, and solid raw material. Compressed air may be used inthis context, but particularly preferred gases include oxygen-free inertgases such as nitrogen, or noble gases such as argon, helium, etc.“Inert gas” as used herein, refers to gases that are not reactive withthe solid raw material, aqueous solvent, and aqueous extract and that donot significantly affect the flavor or fragrance characteristics of theaqueous extract. Preferred gases, so as not to adversely affect theflavor of the extract, are also essentially insoluble, only sparinglysoluble, or not very soluble in the aqueous solvent. For example, gasessuch as carbon dioxide, which is very soluble in the aqueous solvent andcauses “carbonation” thereof, are generally not preferred for use in theinvention. It is also preferable to supply the gas to the vessel atambient or sub-ambient temperature so as to beneficially cool the solidraw material and prevent release of off-flavors/fragrances into theextract.

The steps of the inventive method outlined above may be modified, orcertain steps may be deleted, or additional steps added, according tothe needs and desires of the operator. For example, in some embodimentsof the method, the static pressure-treat step can be omitted. In such anembodiment, after filling the internal volume of the vessel with dryroasted coffee, a continuous flow of aqueous solvent can be establishedthrough the coffee whose dynamic pressure drop is controllable byadjustment of the controllable outlet valve on the outlet line throughwhich extract is collected, and/or by controlling the inlet flow rate ofaqueous solvent. Then, after supplying a desired predetermined volume ofaqueous solvent for extraction, the solvent flow is discontinued and theextract remaining in the wet coffee is purged with a gas as previouslydescribed. In some embodiments where a particularly concentrated extractis desired, the predetermined volume of aqueous solvent supplied asdescribed above is essentially equal to the void volume of the bed ofthe dry, roasted coffee contained within the vessel.

The inventive methods outlined above are also flexible and can be usedto provide a variety of extracts of differing concentration and degreeof extraction from a single quantity of solid raw material. For example,the same quantity of solid raw material can be subjected to multiple,repetitive application of the methods described above to produce avariety of extracts from the same given quantity of solid raw material,each extract having a different concentration and flavor/fragrancecharacteristics indicative of the degree of extraction, with theextracts produced by the first-pass extraction procedure being the mostconcentrated and having the sweetest flavor/fragrance characteristics,and with subsequent extracts being progressively weaker and includingmore bitter and acidic taste/flavor components. Using such a multi-cyclemethod to perform multiple extractions can allow for custom productionof a variety of extracts for a variety of purposes, with even moreextracts being obtainable by selective combinations of two or more ofthe above extracts, while at the same time increasing the utilizationand yield from a given batch of raw material. The modified, multi-cyclemethod here described can be analogous, in some embodiments, to theproduction of various quality olive oils (e.g. extra virgin, virgin,etc.) from multiple pressings of the same olives. In the present case,various quality coffee extracts can be produced from multiple cyclesutilizing the same batch of roasted coffee. In addition, if desired, theextract produced from one cycle of the extraction can be recycled andused as the aqueous solvent for a subsequent extraction cycle eitherwith the same charge of solid raw material or a fresh load of solid rawmaterial.

Also, as described in more detail below, the extracts produced at higherlevels of extraction of the roasted coffee, which are typically morediluted with aqueous solvent, can, in some embodiments, beadvantageously concentrated in coffee solids by removing a portion ofthe aqueous solvent from the extract as a permeate using the inventivefiltration methods, so that they have a solids concentration similar toor exceeding that of the extract produced by the first-pass extraction.Blended extracts, having more balanced sweet/bitter flavor/fragrancecharacteristics, can then be produced by selective mixing of first-passextracts with subsequent extracts that have been concentrated withoutany dilution in the overall solids concentration. Alternatively, theextracts may be mixed together after extraction and prior tode-watering, and the combined extract then subjected to de-watering to adesired final coffee solids concentration. Furthermore, the aqueoussolvent removed from the extracts by certain of the inventive filtrationmethods, such as reverse osmosis or nanofiltration, may containsubstances (e.g. caffeine) that render it commercially valuable as aproduct. The aqueous solvent removed as permeate from the extracts bycertain inventive filtration methods, such as reverse osmosis, may alsohave enhanced salvation power for performing subsequent coffeeextractions owing to the solvent having a lower level of mineralhardness. Such a permeate can be re-used, in some embodiments, as theaqueous solvent, or a component thereof, for performing subsequentextraction cycles on a previously extracted quantity of roasted coffee,or can be used as the aqueous solvent, or a component thereof, forperforming a new, first-pass extraction on a fresh charge of roastedcoffee.

One embodiment of an industrial-scale extraction apparatus and system 10for performing the methods according to the invention is shownschematically in FIGS. 1-4. It should be noted that some components thatwould be apparent to the skilled artisan are not necessarily shown inthe figures, and that the particular arrangement of components is onlyillustrative, which components may be repositioned, or otherwiseinterconnected, substituted, or combined as apparent to the skilledartisan. Referring first to FIG. 1, the apparatus includes a cylindricalpressure vessel 11 having a removable top plate 12 and a removablebottom plate 13. The apparatus can be disassembled to allow forinspection, clean out, and/or replacement of internal components. Inother embodiments, especially for small-scale systems, the vessel may bea single component that does not disassemble. Top plate 12 and bottomplate 13 are attached to integral flanges on the main cylindrical body11 via a plurality of connectors 14, which may be of the nut and bolttype. Typically, a sealing gasket or washer will be included between theplates 12 or 14 and the flanges on the body 11 to make a pressure-tightseal. While the top and bottom plates in the illustrated embodiment havean essentially flat, plate-like configuration, in other embodiments,especially for very large capacity extractors, for example those able tohold 1000 lbs. or more of solid raw material, one or both of the top andbottom “plates” may have a dome-like, semi-hemispherical shape to enableit to withstand higher pressures for a given cross-sectional thickness.In some embodiments, where disassembly of the vessel is not critical,the top and/or bottom plates may be integrally formed with the maincylindrical body, or attached thereto with a permanent attachment means,such as by welding, to increase the leak resistance of the vessel and/oreliminate the need for gaskets and connectors. The vessel, and othercomponents in contact with the aqueous extract or aqueous solvent, arepreferably constructed of a substance that is relatively inert andnon-reactive, such as, for example stainless steel. The pressure vessel11 is constructed and arranged to withstand maximum foreseeableoperating pressures. In one particular embodiment as shown, the vessel11 can be sized to hold about 300 lb. of roasted coffee. The internalvolume 75 of the vessel 11, shown in the cross-sectional view of FIG. 4,can have an internal diameter of about 24 inches, a height of about 48inches and a volumetric capacity of about 12.5 cubic feet (about 90gallons). The vessel is supported on a firm, solid surface 16 by aplurality of support legs 15. In another exemplary embodiment, thevessel can be sized to hold about 1300 lbs. of roasted coffee, can havean internal diameter of about 38 inches, a height of about 96 inches,and a volumetric capacity of about 62.5 cubic feet.

Referring to FIG. 1, coffee, or another solid raw material, is insertedinto the vessel 11 through one or both of raw material lines 17 and 19each in communication with an orifice through top plate 12. Each rawmaterial line includes a valve, 18 on line 17, and 20 on line 19, thatmay be opened to insert coffee, and subsequently closed to seal thevessel 11. Typically, when inserting the coffee into the vessel 11, thecoffee is inserted through at least one valve, while at least one othervalve on the apparatus is open to the atmosphere to allow displaced airto escape. In other embodiments, instead of the extractor being providedwith two raw material lines, a single raw material line, preferablycentered in the top plate, may be provided. In some embodiments,especially for very large extractors, the roasted coffee may be insertedinto the vessel by feeding the roasted coffee to the raw materialline(s) with a screw auger, or other type, feeder (not shown), which canbe mounted to a valve (e.g. 18 and/or 20) included on the raw materialfeed line. In certain such embodiments, the screw auger, or other typefeeder can be operated automatically to fill the vessel and discontinuefeeding when the vessel is filled to a desired, predetermined level. Insuch an embodiment, the vessel can also include a level sensing probe(not shown), such as those commonly employed in the food and dairy artsfor detecting the level of materials in tanks, which may be electricallycoupled to a controller that is programmed/configured to shut off thefeeder when a desired, preset level of material is detected in theextractor.

The positioning of the raw material lines is more clearly seen in thetop view shown in FIG. 2. In other embodiments, the lines may bepositioned differently from that shown, or the apparatus may have more,fewer, or no raw material inlet lines. For example, for some very largeextractors, it may be beneficial to include four, or more, raw materialinlet lines to decrease the time required to fill the vessel. Aspreviously discussed, for some extractors, a single raw material inletline may be provided, or, for small scale extractors, the vessel mayhave no raw material inlet lines, in which case, the vessel would needto be disassembled to be filled with solid raw material.

While the vessel 11 is being filled with the solid raw material, in someembodiments, the vessel can be agitated in order to promote settling ofthe material within the internal volume 75 of the vessel. For theembodiment shown in FIG. 1, agitation is provided by a gas-operated binvibrator 70 connected to an external supply 41 of gas via line 72 andvalve 71. For embodiments utilizing a bin agitator, it is preferred thatthe bin agitator is located at a location positioned at a distance fromthe bottom plate 13 about one third the height of the vessel. Otherembodiments of the apparatus 10 do not include the bin vibrator. In suchembodiments, agitation may be provided if desired, for example, bystriking the vessel 11 with a rubber or wooden mallet, or by placing theapparatus on a vibrating platform. Alternatively, instead ofdistributing and settling the solid raw material through use ofagitation, a distributor element could be included within the internalvolume 75 of the vessel 11 to accomplish the same purpose.

As shown in FIGS. 1, 2 and 4, the apparatus 10 also includes an aqueoussolvent inlet line 46 (see FIGS. 2 and 4) in fluid communication with anexternal source of hot water 32 via line 49 and valve 47. Included online 46 is a temperature reading device 48 to measure the temperature ofthe fluid in line 46 and/or the temperature of internal volume 75 of thevessel 11. In the embodiment shown, the temperature of internal volume75 of the vessel 11 is controlled by controlling the temperature of thehot water supply 32. In alternative embodiments, especially thoseinvolving relatively small-scale extractors, vessel 11 may be directlyheated, for example by a steam jacket or hot water jacket, or byintegral electrical resistance heating or other heating methods apparentto the skilled artisan. As shown in FIG. 4, aqueous solvent inlet line46 is in fluid communication with a spray head 63 located within theinternal volume 75 of the vessel 11. Spray head is constructed andarranged to relatively evenly distribute the hot water over the top ofthe bed of solid raw material formed in the internal volume 75. Avariety of industrial spray heads can be used for this purpose, such asa multiple stream solid washing nozzle (Lechler, St. Charles, Ill.). Theoutlets of the spray head will preferably be positioned above thetypical fill line 65 of the bed of solid raw material.

Also included on the top plate 12 of the vessel 11 is a gas inlet/ventline 33 (see FIG. 1) including a tee connector 34. Tee connector 34 isin fluid communication with an external source of compressed gas 41 vialines 39 and 40 and valve 38, and also with the atmosphere via valve 35and vent line 36. In alternative embodiments, instead of having a singleinlet line in fluid communication with both a source of compressed gasand a vent line via a tee connector, the vessel could instead beprovided with two separate lines that communicate directly with theinternal volume 75 of the vessel. Having a single inlet line in fluidcommunication with two external lines that are not simultaneously used,as shown, reduces the number of perforations that need to be made in theplates 12 and 13 of the vessel 11. While filling the internal volume 75of the vessel 11 with aqueous solvent through line 46 in top plate 12and/or through line 23 in bottom plate 13, and/or through tangentiallydirected line(s) 42 and/or 55, line 33 can be used to vent or “burp”displaced air from the vessel by closing valve 38 and opening valve 35.In embodiments including, as mentioned above, automatic level detectionwithin the vessel, a level detection probe within the vessel can beconfigured to detect the liquid level contained within the vessel, andto control burp valve 35 and the valve(s) on the aqueous solvent feedline(s) through which aqueous solvent is fed to the vessel to performthe above-described fill/burp procedure under automatic control. Whilepressurizing the internal volume 75 of the vessel during thepressure-treat step or while purging residual extract from the bed afterextraction, line 33 can act as a gas inlet line by closing valve 35 andopening valve 38. Line 39 includes a pressure measuring device 37 thatis used to measure the pressure of the internal volume 75 of the vessel11 during operation.

As shown in FIG. 1, included on bottom plate 13 is an extract outletline 23 in fluid communication with the internal volume 75 of the vessel11 via a drain hole in bottom plate 13. Aqueous extract exits vessel 11via line 23 passes through tee 24, controllable valve 25, and line 27 toa chiller 28 that reduces the temperature of the extract to atemperature below room temperature to prevent degradation to the flavorand/or loss of fragrance. The chilled extract exits chiller 28 via line29 and can be collected in a container 30. In preferred embodiments,container 30 is a sealable container whose headspace is filled and/orflushed with an inert gas, such as nitrogen, in order to preventexposure of the extract to atmospheric oxygen. As described in moredetail below in the context of FIGS. 6-8, container 30 can also serve asthe feed container to the inventive solvent-removal filtration systemutilized, in some embodiments, for concentrating the coffee extract.Also in fluid communication with tee 24 and line 23 via valve 26 andline 31 is hot water supply 32; hot water supply line 31 can be used, incertain embodiments, for filling the vessel with aqueous solvent throughline 23 after filling the vessel with roasted coffee, as previouslydescribed, and, in addition, these lines are used in connection with thenovel spent material flush out methods described in more detail below.

In order to prevent the solid raw material from exiting the vessel vialine 23 during flow-through extraction, a filter element is includedwithin vessel 11 upstream of line 23. A preferred arrangement of filterelement is shown in FIG. 3 and, in cross-section, in FIG. 4. Thepreferred filter element includes of a porous screen 58 having openingstherein that are small enough to retain essentially all of the solid rawmaterial. In one preferred embodiment, the porous screen comprises acommercially available (e.g. U.S. Filter, Johnson Screen Division, St.Paul, Minn., Model 63V, having a slot size of 0.020″) wedge wire typescreen, with a surface oriented facing the bed of solid raw material,having about 25% open space. As shown more clearly in FIG. 4, porousscreen 58 is supported by bottom plate 13, which plate includes aplurality of channels and grooves 59 constructed and arranged to directthe flow of aqueous extract that passes through porous screen 58 toaqueous extract outlet line 23. Porous screen 58 provides a support, andmeans of retention for the bed of solid raw material and has a diameterthat is preferably essentially equal to the internal diameter of vessel11. Porous screen 58 can be attached to bottom plate 13 via screws 67,or any other appropriate connecting means. In some other embodiments,the filter element may be positioned elsewhere in the internal volume75. In other embodiments, the filter element could be a smaller screenor filter positioned directly upstream of, or even within extract outletline 23. A wide variety of arrangements of the filter element arepossible as would be apparent to the skilled artisan; all of which areincluded within the scope of the invention.

As previously mentioned, extraction apparatus 10 also includes a novelarrangement of components for flushing spent solid raw material from theinternal volume 75 of the vessel 11, and for cleaning out the vesselafter an extraction has been performed and prior to a subsequentextraction. The arrangement of components illustrated allows spent rawmaterial to be flushed from extraction apparatus 10, and allows forclean-out without the need for disassembly of the apparatus. In theillustrated embodiment, as shown in FIG. 1, the wash-out system includesspent material outlet waste line 21, including valve 22, that is influid communication with a waste collection system, such as a sewer. Asshown in FIG. 4, outlet port 60, opening into the internal volume 75 ofthe vessel 11 from line 21, is preferably positioned directly aboveporous screen 58. In alternative embodiments, not shown, instead ofoutlet port 60 comprising an orifice through the side wall of vessel 11positioned above the screen, the outlet port may instead be located inthe bottom plate and communicate with the internal volume of the vessel,for the purposing of flushing out spent solid raw material, through ahole in the porous screen positioned adjacent to, and in fluidcommunication with, the outlet port in the bottom plate. For suchalternative embodiments, a gasket, or other sealing means, can beincluded to fluidically isolate the spent material outlet port from thedownstream side of the porous screen, where extract collects and flowsfrom the extractor, in order to prevent contamination of the collectedextract with spent solid raw material, as would be apparent to those ofordinary skill in the art.

A preferred wash out configuration includes a fluid supply lineconstructed and arranged to back-flush the filter element. In theillustrated embodiment, the back flush is performed through line 23 byfirst closing valve 25, and then opening valve 26 so that a fluid, inthe illustrated embodiment hot water from pressurized hot water supply32, will enter the vessel 11 via line 23, which now acts as an inletflush line, and thereby back flush the porous screen 58. Typically,valve 22 will be open during the flush-out procedure to allow spentmaterial to be removed from the vessel 11; although, in someembodiments, valve 22 may be closed during at least part of theflush-out procedure to allow the internal volume 75 of the vessel 11 toat least partially fill with liquid in order to disperse and fluidizethe spent material. In alternative embodiments, line 31 may also be influid communication with a source of pressurized gas. In suchembodiments, either gas, liquid, or a two-phase gas-liquid fluid can beused to back flush the filter element and wash out the spent solid rawmaterial.

Also included in the preferred embodiment are additional tangentialflush lines 42 and 55 (see FIGS. 1 and 3) which are in fluidcommunication with a source of pressurized cold water 45 via valve 43and line 44 for flush line 42, and valve 56 and line 57 for flush line55, and with hot water supply 32 via connection to lines 44 and 57, forexample by connector line 44 a and three-way valve 43 a. As previouslydiscussed, these tangential flush lines can also be advantageously usedas hot aqueous solvent fill lines during initial filling of the vesselwith aqueous solvent after filling with solid raw material at thebeginning of the extraction process. Both lines 42 and 55 are positionedto be roughly tangent to the cylindrical wall of vessel 11 with openings(e.g. see FIG. 4 for opening 61 of line 55) into the internal volume 75of the vessel 11 positioned vertically above the porous screen 58 atabout the same height, in the illustrated embodiment, as the outlet port60 to spent material outlet line waste 21. The tangential orientation ofthe flush lines 42 and 55 with respect to the vessel walls tends tocreate a swirling, vortex-like flow pattern of wash fluid within thevessel, which assists in thoroughly removing the spent material from thevessel 11 via line 21. In addition, at least one of the tangential flushlines (line 55 in the illustrated embodiment) is preferably positionedso that the opening 61 of the line in the vessel wall directs a streamof flush fluid obliquely incident upon the outlet port 60, through whichspent material exits the vessel 11, in order to drive the slurriedmaterial through line 21 to waste and prevent plugging of outlet port60. In other embodiments, more than two tangential flush lines may beused to improve removal of spent material, for example for very largeextractors, or alternatively only a single line may be used. For smallextractors, tangential flush lines are typically not required toeffectively remove the spent material from the vessel.

Also included, in the illustrated embodiment, and seen most clearly inFIGS. 2 and 4, is an optional wash down line 62 through top plate 12.Wash down line 62 is in fluid communication with a supply of pressurizedcold and hot water via tee 50, and valve 51 and line 53 (cold water), orvalve 52 and line 54 (hot water). Wash down line 62 is preferablyconnected to a rotating spray nozzle 64 that is positioned withininternal volume 75 of the vessel 11. Rotating spray nozzle 64, whensupplied with pressurized fluid, will rotate and spray fluid in order toeffectively wash down the walls and internal surface of the top plate 12and the vessel 11. A variety of commercially available rotating spraynozzles can be used for this purpose. The illustrated embodiment employsa whirling tank nozzle (Lechler, St. Charles, Ill.). Other embodimentsmay include additional wash down lines and rotating spray nozzles,while, in yet other embodiments, wash down line 62 may be eliminated,and wash down may be performed by utilizing line 46 and spray head 63alone. In some embodiments, the water employed for washing purposes mayinclude one or more cleaning and/or corrosion inhibiting agents as knownin the art.

Operation of the Extraction Apparatus

With reference to the apparatus illustrated by FIGS. 1-4, an exemplarycoffee extraction procedure using the above described apparatus canproceed as follows. At the start of the procedure, all valves are in aclosed position. The vessel 11 is then preheated by opening valve 52 toestablish a flow of pressurized hot water into the vessel throughrotating spray nozzle 64. When the pressure within the vessel, as readby pressure measuring device 37, is approximately equal to that of thehot water supply pressure, valve 25 downstream of extract outlet line 23is opened to establish a flow of hot water to drain or chiller 28, andthen valve 52 is closed. Valve 38 is then opened to supply pressurizedgas, preferably an inert gas, such as nitrogen, to the vessel via line33. The gas flow is maintained until no more liquid is observed leavingthe vessel. The gas flow is then discontinued by closing valve 38, andthe vessel is equilibrated to atmospheric pressure. Valve 25 downstreamof extract outlet line 23 is left open.

A desired quantity of dry coffee is next added to the vessel by openingvalves 18 and 20 on raw material lines 17 and 19 and pouring or feedingcoffee into the vessel through lines 17 and 19 until the vessel isessentially full. The dry coffee can then be settled by opening valve 71to supply gas flow to bin vibrator 70, or alternatively, tapping thevessel with a mallet, if desired. Alternatively, the coffee can besettled without agitation of the vessel by briefly opening valve 52and/or 47, and/or 26, and/or 43, and/or 56 to apply hot water to thecoffee at one or more intervals during the addition of dry coffee, orafter the coffee has been added, to moisten and settle the coffee. Ifdesired, more coffee may now be added to more completely fill the vesselbefore closing valves 18 and 20. Valve 47 is then partially opened tosupply pressurized hot water to the vessel via aqueous solvent inletline 46. Upon the first sign of extract discharge from line 29, valve 25downstream of extract outlet line 23 is closed and the vessel is filledwith a desired quantity of hot water. Valve 35 on vent line 36 is atleast partially opened, either manually or via automatic control, atsome point during the process of filling the vessel with water to “burp”out gas; the valve 35 is closed when extract is observed to flow fromline 36. The volume of hot water added to the coffee is preferably equalto or greater than the void volume of the bed of coffee so that all ofthe coffee is wetted. In some embodiments, the volume is essentiallyequal to the void volume present in the bed. As discussed above, thevessel can also be filled with hot aqueous solvent at this stage throughone or more of lines 46, 23, 42, and 55. The vessel is then furtherpressurized, either with pressurized hot water by opening valve 47, orwith pressurized gas by opening valve 38, to a desired pressure(typically about 40-132 psig) for performing the static pressure-treatstep. The pressure is maintained in the vessel without flow for adesired period of time (typically about 10-30 min.). Next, valve 25downstream of the extract outlet line 23 is controllably opened toinitiate a desired flow rate of extract through line 27 and chiller 28and into collection container 30. For some embodiments during this step,depending on the desired strength of the extract and degree ofextraction, valve 47 can be opened and a measured quantity of hot watercan be added to the vessel to further extract the coffee within thevessel via a flow-through extraction step. During such flow-throughextraction, the pressure within the vessel can be controlled byadjusting valve 25 on the extract outlet line 23, and/or valve 47 on thehot water inlet line 46. For embodiments where additional hot water hasbeen added after the pressure treat step, after the desired quantity ofadditional solvent water has been supplied during the flow-throughextraction, valve 47 is closed to discontinue flow from the hot watersupply. Valve 38 is then opened so that compressed gas enters the vesselvia line 33 in order to purge residual extract from the void volume ofthe bed of coffee. Valve 47 is closed when gas flow is observed fromextract collection line 29. At this point, extraction is complete andthe vessel may be reused for a subsequent extraction with the samecharge of coffee to produce an extract having more bitter/acidicflavor/fragrance characteristics of a more exhaustively extractedroasted coffee, or the spent coffee can be removed from the vessel. Forembodiments where a maximum-strength extract is desired, the extract canbe purged from the bed with the gas flow immediately after thepressure-treat step without supplying additional hot solvent water for aflow-through extraction step.

In order to remove the spent grounds from the vessel, valve 25 on theextract outlet line 23 is closed and valve 22 on spent material wasteline 21 is opened. Valve 26 is then opened to back flush the porousscreen 58 with pressurized water through line 23; valves 43 and 56 areopened to supply pressurized water flow to tangential flush lines 42 and55 respectively, and valve 51 or 52 is opened to supply pressurized coldor hot water to rotating spray nozzle 64 via line 62. After the flow ofliquid exiting the waste line 21 is observed to be clear and clean, thevalves supplying pressurized water to the various lines for flush outare closed; valve 22 on waste line 21 is closed, and the process iscomplete. The extract exit line 27, chiller 28, and extract collectionline 29 can also be flushed by opening valve 25 followed by valve 26 todirect pressurized water from source 32 through line 31, valve 26, tee24, valve 25, line 27, chiller 28, and line 29.

As discussed previously, the invention also provides methods forremoving excess solvent from consumable extracts in order to concentratethe extracts with respect to a dissolved or suspended consumablematerial. It should be understood that the inventive filtration-basedconcentration methods described herein can be utilized for concentratinga wide variety of consumable extracts produced from extracting a widevariety of solid raw materials, such as those discussed previously inthe context of the inventive extraction methods. It should also beunderstood that, while in some preferred embodiments, the inventiveconcentration methods are utilized for concentrating extracts producedusing the above-described inventive extraction methods and apparatuses,the novel concentration methods described herein can also, in otherembodiments, be utilized for concentrating consumable extracts producedby a wide variety of other extraction methods for forming consumableextracts known in the prior art. As with the above-discussed extractionmethods, the inventive extract concentration methods will be describedbelow with reference to a particular embodiment involving theconcentration of an aqueous extract of roasted coffee; however, itshould be understood that the methods and apparatuses described hereinare not so limited and that the methods and apparatuses may be employedwith a wide variety of other consumable extracts produced by a widevariety of extraction methods within the scope of the present invention.

FIG. 5 is a conceptual diagram of a portion of filtration-based systemfor concentrating a consumable extract, for example a coffee extract asproduced by the extraction methods described above. FIG. 5 shows asection of a filter 100 including a filter medium 102, which separatesthe filter into a retentate side 104 and a permeate side 106. The term“filter” as used herein refers broadly to any apparatus or systemcontaining a filtration medium and able to perform filtration of aliquid. The term “filtration medium” as used herein refers to anymedium, material, or object having sufficient hydraulic permeability toallow at least one component, for example a solvent, of a liquidsolution or suspension, for example a coffee extract, to pass throughthe medium, while, at the same time, retaining and preventing passage ofat least one other component of the solution or suspension, for examplea dissolved solute component. A wide variety of filters and filter mediamay be used, according to the invention, for concentrating consumableextracts, for example coffee extracts.

Filters that may be utilized according to the invention can include awide variety of configurations as known in the art, for examples, gelpermeation filters, and membrane-based filters in a wide variety ofconfigurations, such as flat sheet filters, hollow fiber filters, spiralfilters, tube membrane filters, and other configurations as apparent tothose of ordinary skill in the art. Preferred filters employ afiltration medium comprising a semipermeable membrane(s). Such membranescan be fabricated from a wide variety of materials, such as ceramics andother inorganic materials, or organic materials, such as polymers.Certain preferred embodiments of the invention utilize a filtrationmedium comprising a semipermeable polymeric membrane(s). Such polymericmembranes can be fabricated from a wide variety of polymeric materialsand can be constructed to have a wide variety of porosity and molecularsize exclusion characteristics. Such membranes are well known in thefiltration arts, and are widely commercially available. Polymericmembranes can potentially be constructed, for example, from polymersincluding, but not limited to, polyamides, cellulose and/or celluloseesters, polysulfone, polycarbonate, polyesters, polyethylene oxide,polypropylene oxide, polyvinylidene fluoride, poly(tetrafluoroethylene),poly(acrylates), others, and in co-polymers and/or combinations as knownin the filtration and membrane separation arts.

Referring to FIG. 5, the basic steps of the inventive concentrationmethod can involve supplying an extract to be concentrated to theretentate side 104 of filter 100, passing a permeate comprising at leasta portion of the solvent component of the extract through filtrationmedium 102, as shown by arrow 108, and collecting the concentrated andsolvent-reduced extract from the retentate side 104 of the filter, and,optionally, collecting the permeate from the permeate side 106 of thefilter. Filter 100 may, in some embodiments, be operated in a dead-endmode, with essentially no flow or very little flow of retentate directedtangential to filter medium 102, or, in more preferred embodiments, thefilter can be operated in a cross-flow mode as shown, with a componentof retentate flow (arrows 109) directed tangentially to the filtrationmedium, in order to prevent fouling and increase the filtrationefficiency of the filter.

Filter medium 102 is preferably selected to have a porosity andmolecular weight cutoff able to allow passage of a solvent component ofthe extract, for example water, while retaining on the retentate side ofthe filter dissolved or suspended solutes which form flavor and/orfragrance components of the extract. For embodiments where the method isused for de-watering a coffee extract, filter membrane 102 is preferablyselected so that it is able to freely pass water, while, at the sametime, retaining, on the retentate side, a substantial fraction of thedissolved coffee solids in the extract. A “substantial fraction” as usedherein in the present context refers to a fraction of coffee solids thatis necessary to impart to the retained extract an “effective amount” ofvarietal components, as defined previously. In some preferredembodiments, at least 90% of the coffee solids are retained, and in evenmore preferred embodiments, essentially all of the dissolved solidscomprising flavor and/or fragrance components are retained on theretentate side of the filter by the filtration membrane. For preferredembodiments involving de-watering of coffee extracts, the filtrationmembrane 102 comprises a reverse osmosis membrane or a nanofiltrationmembrane. A “reverse osmosis membrane” as used herein refers to amembrane having an average pore size of less than about 0.003 μm and amolecular weight cutoff of less than about 1,000 Da. A “nanofiltrationmembrane” as used herein refers to a membrane having an average poresize within the range of between about 0.001 μm and about 0.01 μm, witha molecular weight cutoff within the range of between about 300 Da andabout 20,000 Da. In one preferred embodiment, filter membrane 102comprises a polyamide nanofiltration membrane, in another preferredembodiment, the filter membrane comprises a spiral-wound, multi-layer,thin film composite reverse osmosis membrane such as FILMTEC® reverseosmosis membranes available from The Dow Chemical Company.

The concentration method, according to the invention, for forming aconcentrated coffee extract via de-watering a more dilute precursorextract can proceed by supplying the relatively dilute coffee extract tothe retentate side 104 of filter 100 at a pressure P₁ sufficiently inexcess of pressure P₂ on permeate side 106 of the filter to forcesolvent through membrane 102 while retaining a substantial fraction ofcoffee solvents on retentate side 104, and, thus, increasing theconcentration c₁ of dissolved coffee solids in the retentate above thatof the concentration in the precursor coffee extract. The filtrationprocess can be continued until a desired concentration c₁ is achieved.The system can be monitored by, for example, measuring the volume ofpermeate collected from permeate side 106 of the filter and comparingthe volume of permeate collected to the initial volume of coffee extractbefore commencement of the filtration process and/or by measuring theconductivity of the retentate and determining the dissolved solidsconcentration by comparison with a calibration curve. For example, forembodiments where it is desired to reduce the volume of solvent in theinitial coffee extract by a factor of 2, and thus increase theconcentration of coffee solids in the concentrated extract byapproximately a factor of 2, the filtration process can be continueduntil a volume of permeate approximately equal to one half the initialvolume of extract supplied to the retentate side of the filter iscollected.

The filter size, for example as measured by the total area of the planarsurface 110 of membrane 102 available for filtration, the applieddifferential pressure (P₂−P₁), flow rates, and other operatingparameters of the filter, as well as the molecular weight cutoff andpore size of the filter membrane, must be selected according to theneeds of each particular desired application. The selection of suchoperating parameters can be based upon the total volume of extractdesired to be concentrated within a particular time period, theconcentration and size of the dissolved and/or suspended components inthe extract which are desired to be retained, the particularconfiguration of the filter, and other factors as apparent to those ofordinary skill in the filtration arts, and as described, for example inmany standard texts such as Perry's Chemical Engineers' Handbook (SixthEdition, Robert H. Perry, Don W. Green, and James O. Maloney, Eds.,1984, Chapter 17), incorporated herein by reference. As described belowwith reference to FIGS. 6-8, many filtration systems for performingreverse osmosis or nanofiltration are commercially available and aresized and designed for processing a wide variety and quantities ofliquid solutions/suspensions.

The particular selection of operating parameters must be made, for aparticular application, by routine experimentation and optimization. Forexample, screening tests may be performed for selecting appropriatetypes of filtration membranes and molecular weight cutoffs by performinga trial filtration of a dilute, for example beverage strength, coffeeextract with a particular membrane until a desired degree of de-wateringis obtained, followed by collecting the concentrated extract from theretentate side of the filter, reconstituting the concentrated extractwith a volume of fresh solvent water equal to the volume of permeateremoved during filtration, and comparing the taste and/or flavorcharacteristics of the reconstituted extract to that of the initial,beverage-strength extract, for example by cupping as describedpreviously. Operating pressures, filter sizes, flow rates, and otheroperating parameters may be selected on the basis of well knownprinciples of membrane filtration/separations, described in many wellknown and readily available texts describing filtration/reverse osmosis,for example in Perry's Chemical Engineers' Handbook referenced above andMcCabe, Smith, and Harriott, Unit Operations of Chemical Engineering,Fourth Edition, Kiran Verma and Madelaine Eichberg, Eds., 1985,incorporated herein by reference, combined with routine experimentationand optimization. Typically, for a given filtration membrane, having amolecular weight cutoff and porosity selected as described above, thetotal membrane area is selected to provide a desired range of permeatethroughput (i.e., volume filtered/time) within an acceptable range ofdifferential pressure, as dictated by the material limitations of thefiltration medium and filter system components.

As shown in FIG. 5, upon filtration of a coffee extract to form a moreconcentrated coffee extract, over time, a layer of coffee solids 112 mayhave a tendency to build up on the retentate side 110 of filter membrane102. This can be undesirable from the standpoint both of decreasing thefiltration rate through membrane 102 at a given differential pressure,and from the standpoint of a loss of coffee solid concentration c₁ inthe retentate collected from retentate side 104 of the filter. In somepreferred embodiments, at one or more points during the filtrationprocess, membrane 102 can be back-flushed by supplying, for a briefperiod, a relatively small volume of a back-flush solvent (which, insome embodiments, may comprise permeate collected during the filtrationprocess) to the permeate side 114 of membrane 102, and forcing theback-flush solvent through membrane 102 from permeate side 106 of thefilter to retentate side 104 of the filter, in the direction of arrow116, by creating a pressure P₂ on the permeate side exceeding pressureP₁ on the retentate side of the filter. In this way, coffee solidsforming a layer 112 on membrane 102 can be dislodged from the membraneto improve its overall filtration rate, upon subsequent filtration, andalso to re-suspend coffee solids 112 in the concentrated coffee extractpresent on retentate side 104 of the filter. Thus, using such aback-flush procedure can increase the total recovery of, andconcentration of, coffee solids in the de-watered extract, which canlead to formation of a more valuable de-watered extract product withenhanced retention of the flavor/fragrance characteristics of theinitial precursor coffee extract before concentration. It is alsocontemplated that the permeate collected from permeate side 106 of thefilter during the de-watering of coffee extract can, in certainembodiments, contain commercially valuable components, for examplecaffeine. For such embodiments, this permeate may be collected andutilized as a component or ingredient in other food or pharmaceuticalproducts.

One illustrative embodiment of a filtration system for use, according tothe invention for de-watering and concentrating a coffee extract isshown in FIG. 6. Filtration system 150, as shown, is representative of avariety of commercially available reverse osmosis/nanofiltration systemsavailable, for example, from the PROSYS Corporation (Chelmsford, Mass.).In one particular embodiment of the invention, filtration system 150comprises a modified PROSYS Model No. 400 Series Reverse Osmosis Systemhaving a nominal design permeate flow rate of 1 gal./min. The system, asconfigured in the illustrated embodiment, is constructed fromfood/pharmaceutical grade materials. The system may further include, insome embodiments, a variety of additional valves, switches, pressuregauges, transducers, temperature probes, electronic/microprocessor-basedmonitoring/process control hardware and software, etc., in addition tothe particular components illustrated, as would be apparent to those ofordinary skill in the reverse osmosis/nanofiltration arts. System 150,as configured in the illustrated embodiment, includes four filtrationcartridges 152, 154, 156, and 158, which are arranged in a parallelconfiguration. Each of the filter cartridges, as illustrated, includes aModel No. TFC®-4921S Spiral-Wound Filter Cartridge (Koch MembraneSystems, Wilmington, Mass.). The filtration cartridges each includeabout 7.5 m² of filter membrane area. The filter membrane is configuredin a spiral-wound fashion with a fiberglass outerwrap, and thesemi-permeable membrane comprises a polyamide membrane of thenanofiltration type. The maximum operating pressure for the membranecartridges is about 350 psi with a typical operating pressure of about80 psi. System 150 further includes a 5 μm cartridge prefilter 160upstream of filter cartridges 152, 154, 156, and 158. In the illustratedembodiment, extract is pressurized and supplied to the filter cartridgesby means of a pump 162, which, in the illustrated embodiment, comprisesa multi-stage centrifugal pump with stainless steel wetted components.In other embodiments, pump 162 may be supplemented or replaced by asystem for pressurizing the container/vessel 30 holding extract 164 tobe concentrated. In one preferred embodiment, such an extractpressurization system can comprise a source of compressed gas 166coupled to container 30 via line 168 and valve 170, which is configuredto supply compressed gas at a sufficient pressure for driving extractthrough filtration system 150. For embodiments where extract 164 ispressurized with an external source of pressurized gas, it is preferredthat the pressurized gas comprise an inert gas, for example nitrogen. Inpreferred embodiments, extract 164 in container 30 is maintained incontact with and blanketed by an inert gas supplied be source 166 duringprocessing in order to minimize its exposure to oxygen. The inert gasfrom source 166 can also, in some embodiments, be used at the end ofprocessing, after collection of the concentrated extract product fromthe system, to “blow out” residual retentate from the lines of thesystem and the filtration cartridges for collection.

System 150 can operate as follows for de-watering and concentrating acoffee extract, according to the invention. Unconcentrated extract 164in container 30 can be produced, for example, as described above byutilizing the inventive extraction methods and apparatuses.“Unconcentrated” extract as used herein refers specifically to anextract forming a feed stream to the retentate side of the filterscontained within the system. It should be understood that such“unconcentrated” extracts will, in many cases, already, as produced fromthe inventive extraction methods and apparatus, have a level of coffeesolids concentration exceeding that typical for typicalbeverage-strength extracts. Conversely, a “concentrated” extract, asused in the following description, refers to an extract comprising awater-reduced (i.e. de-watered) retentate product recovered from theretentate side of the filters contained within the system. As describedpreviously, in some preferred embodiments, unconcentrated extract 164can comprise an extract produced from a second or subsequent extractionstep of a given charge of roasted coffee. For embodiments where extract164 is produced from a second or subsequent extraction step of a givencharge of roasted coffee, typically, the concentration of coffee solidsin the extract will be lower, and the degree of dilution with water willbe higher, than for extracts produced during the first-pass extractionof the roasted coffee. It is, therefore, sometimes desirable toconcentrate the second, or subsequent pass extract so that it has aconcentration of coffee solids and degree of dilution that is similar tothat of the first-pass extract. In this way, as described in more detailbelow, the extracts produced according to the invention during thefirst-pass extraction may be blended with extracts produced during asecond or subsequent stage extraction, which have been de-watered tohave an overall concentration similar to that of the first-pass extract,to form blended coffee extracts without substantially diluting theoverall concentration of coffee solids in the first-pass extract.

Extract 164 can be fed, for example by gravity, through valve 172 andline 176 to pump 162 where it is pressurized to the operating pressureof filtration cartridges 152, 154, 156, and 158. The extract then passesfrom pump 162 through line 178 and through pre-filter 160 to manifold180 including a pressure gauge or transducer 182 thereon for monitoringthe retentate side pressure of filtration cartridges 152, 154, 156, and158. In other embodiments, additional pressure gauges/transducers may belocated directly on the individual filtration cartridges 152, 154, 156,and 158. In addition, while in the illustrated embodiment filtrationcartridges 152, 154, 156, and 158 are connected in parallel to amanifold 180, in other embodiments, the filtration cartridges mayinstead be connected in series with respect to each other. From manifold180, extract 164 passes through each of filtration cartridges 152, 154,156, and 158 via line 184 and valve 186, line 188 and valve 190, line192 and valve 194, and line 196 and valve 198 respectively.Unconcentrated extract 164 is fed to the retentate side of the filtercartridges. While flowing through the retentate side of the filtercartridges, at least a portion of the solvent component of the extractpasses through the filtration membrane to the permeate side of thefiltration cartridges, thus forming a more concentrated coffee extracton the retentate side of the filter cartridges and a relatively diluteor coffee solid free permeate on the permeate side of the filtercartridges. The concentrated coffee extract retentate then flows out ofthe filter cartridges and into a concentrated extract manifold 199 vialine 200 and valve 202, line 204 and valve 206, line 208 and valve 210,and line 212 and valve 214 for filtration cartridges 152, 154, 156, and158 respectively. Concentrated extract manifold 199 may include apressure gauge/transducer 216 thereon for monitoring the pressure on theretentate sides of the filter cartridges. The concentrated coffeeextract in manifold 199 flows via line 218 and valve 220 to collectioncontainer 222, for containing concentrated extract 224.

In some preferred embodiments for operating filtration system 150,unconcentrated extract 164 passes through filtration cartridges 152,154, 156, and 158 only single time to form concentrated extract 224 in asingle-pass through the system. In other embodiments, system 150 may beoperated as a multi-pass system, where, in such embodiments, theconcentrated extract is recycled back to container 30 via line 226 andvalve 228. For such embodiments, extract would continue to be pumpedfrom container 30, through the filter cartridges, and recycled tocontainer 30 until a desired quantity of solvent has been removed, aspermeate, and a desired level of concentration of the extract containedin container 30 has been achieved.

Permeate is collected from the filter cartridges via lines 230, 232,234, and 236 and flows into manifold 238, which can have a pressuregauge/transducer 240 thereon, and into permeate collection container242. As previously discussed, permeate 244 may be saved and utilized asan ingredient for additional food/pharmaceutical products or, may bediscarded. In another preferred embodiment, especially where the solventwater comprising permeate 244 has been substantially demineralized bypassage through filtration cartridges 152, 154, 156, and 158, aqueouspermeate 244 can be beneficially used as an extraction solvent forperforming an extraction of fresh, or previously extracted, roastedcoffee, and, for such purposes, may be recycled back to line 46 onextraction system 10, as shown previously in FIGS. 1 and 2. The amountof permeate removed form the extract during concentration proceduredepends, as previously discussed, on the desired final concentration ofthe concentrated extract. For some preferred embodiments involving asingle-pass operating mode, and where a highly concentrated extract isdesired, at least about 50% of the solvent component of the extractsupplied to the retentate side of the filter cartridges is passed to thepermeate side of the filter cartridges, or, for multipass/multicycleembodiments, at least 50% of the solvent component of the initialprecursor unconcentrated extract is removed by the system during themultipass filtration procedure. Also, as discussed previously, for someembodiments, filtration cartridges 152, 154, 156, and 158 may be brieflyback-pulsed or back-flushed, for example by reversing pump 162 and/orsupplying a pressurized quantity of permeate or other back-flush solventto manifold 238. For such embodiments, the filtration media in thefiltration cartridges may be at least partially cleaned and regenerated,and additional coffee solids may be collected from the retentate side ofthe filter cartridges for addition to concentrated extract 224 duringthe back-flush procedure.

A second illustrative embodiment of a filtration system for use,according to the invention for de-watering and concentrating a coffeeextract is shown in FIG. 7. Filtration system 300, in one particularembodiment of the invention, comprises a modified Fluid Solutions ModelNo. 10037 Reverse Osmosis System (Fluid Solutions, Inc. Lowell, Mass.)having a nominal design permeate flow rate of about 12-15 gal./min. Thesystem, as configured in the illustrated embodiment, is constructed fromfood/pharmaceutical grade materials. The system may further include, insome embodiments, a variety of additional valves, switches, pressuregauges, transducers, temperature probes, electronic/microprocessor-basedmonitoring/process control hardware and software, etc., in addition tothe particular components illustrated, as would be apparent to those ofordinary skill in the reverse osmosis/nanofiltration arts. System 300,as configured in the illustrated embodiment, includes five filtrationcartridges 302, 304, 306, 308, and 310. Cartridges 302, 304, and 306 arearranged in parallel and are connected in series with cartridges 308 and310, which are connected in parallel with each other. Each of the filtercartridges, as illustrated, includes three FILMTEC® Model No. BW30-4040spiral-wound filter membrane elements. The filter membrane elements eachinclude about 6.5 m² of filter membrane area. The maximum operatingpressure for the filter membrane elements is about 600 psi with atypical operating pressure of between about 250-400 psi. System 300further includes a 5 μm cartridge prefilter 312 upstream of filtercartridges 302-310. In the illustrated embodiment, extract ispressurized and supplied to the filter cartridges by means of boosterpump 314 and R/O pump 316. In other embodiments, pump 314 and/or 316 maybe supplemented or replaced by a system for pressurizing thecontainer/vessel 30 holding extract 164 to be concentrated. In onepreferred embodiment, such an extract pressurization system can comprisea source of compressed gas 166 coupled to container 30 via line 168 andvalve 170, which is configured to supply compressed gas at a sufficientpressure for driving extract through filtration system 300. Forembodiments where extract 164 is pressurized with an external source ofpressurized gas, it is preferred that the pressurized gas comprise aninert gas, for example nitrogen. Container 30, as illustrated, alsoincludes an inlet line 318, connected to a city water supply via valve320 and an outlet line 322 for draining the container through valve 324.In preferred embodiments, extract 164 in container 30 is maintained incontact with and blanketed by an inert gas supplied be source 166 duringprocessing in order to minimize its exposure to oxygen. The inert gasfrom source 166 can also, in some embodiments, be used at the end ofprocessing, after collection of the concentrated extract product fromthe system, to “blow out” residual retentate from the lines of thesystem and the filtration cartridges for collection.

System 300 can operate as follows for de-watering and concentrating acoffee extract, according to the invention. Unconcentrated extract 164in container 30 can be produced, for example, as described above byutilizing the inventive extraction methods and apparatuses. Extract 164can be fed, for example by gravity, through valve 326 and line 328 tobooster pump 314. Alternatively, or concurrently, extract can be fed tothe system directly from the outlet line of the extractor via line 330and valve 332. The extract is pressurized by booster pump to a pressure,measured by pressure gauge 334, sufficient to pass the extract throughthe prefilter 312. Pressure drop across the prefilter can be determinedby comparison of the pressure measured downstream of the prefilter bypressure gauge 336 to that measured upstream by gauge 334. Aconductivity meter 338 is included to enable the determination of theconcentration of solids in the extract prior to de-watering incartridges 302, 304, 306, 308, and 310, as previously discussed.

The extract is then pressurized to the operating pressure of filtrationcartridges 302, 304, 306, 308, and 310 by R/O pump 316. The extract thenpasses from pump 316 through line 340 and through throttling valve 342,including located upstream and downstream thereof pressure gauges 344and 346 respectively, to manifold 348. In other embodiments, pressuregauges/transducers may be located on the manifold or directly on theindividual filtration cartridges 302, 304, and 306. From manifold 348,extract 164 passes through each of filtration cartridges 302, 304, and306 via line 350, line 352, and line 354 respectively. Unconcentratedextract 164 is fed to the retentate side of the filter cartridges. Whileflowing through the retentate side of the filter cartridges, at least aportion of the solvent component of the extract passes through thefiltration membrane to the permeate side of the filtration cartridges,thus forming a more concentrated coffee extract on the retentate side ofthe filter cartridges and a relatively dilute or coffee solid freepermeate on the permeate side of the filter cartridges. The concentratedcoffee extract retentate then flows out of the filter cartridges andinto a concentrated extract manifold 356 via line 358, line 360, andline 362 for filtration cartridges 302, 304, and 306 respectively. Theconcentrated coffee extract in manifold 356 flows via line 364 to inletmanifold 366 which feeds filter cartridges 308 and 310 via lines 368 and370 respectively. The extract is then further concentrated by filtercartridges 308 and 310 to produce a concentrated a coffee extractretentate which flows out of the filter cartridges 308 and 310 into aconcentrated extract manifold 372 via lines 374 and 376. Theconcentrated extract then flows via line, including pressure gauge 380thereon, through throttling valve 382 to chiller 384. Included on line378 downstream of throttling valve 382 is a flow meter 386 for measuringvolumetric fluid flow of the retentate and a conductivity meter 388 fordetermination of solids content of the concentrated extract. If thesolids concentration of the retentate stream, as determined from theconductivity measurement or otherwise, meets the desired product value,then the concentrated extract can be collected as final product fromline 390 by opening valve 392; otherwise, the extract can be recycled totank 30 via opening valve 394 on line 396 for further processing.

Permeate is collected from the filter cartridges via lines 398, 400,402, and 404 and flows into manifold 408. Manifold 408, in turn, feedspermeate line 410, which has a flow meter 412 thereon. Permeate caneither be sent to drain or collection via opening valve 414 on line, or,if desired, recycled to tank 30 via opening valve 418 on line 420. Asdiscussed previously, for some embodiments, filtration cartridges 302,304, 304, 306, 308, 310 may be briefly back-pulsed or back-flushed, forexample by reversing pump 316 and/or supplying a pressurized quantity ofpermeate or other back-flush solvent to manifold 408. For suchembodiments, the filtration media in the filtration cartridges may be atleast partially cleaned and regenerated, and additional coffee solidsmay be collected from the retentate side of the filter cartridges foraddition to the product concentrated extract during the back-flushprocedure.

A third illustrative embodiment of a filtration system for use,according to the invention for de-watering and concentrating a coffeeextract is shown in FIG. 8. Filtration system 500, is similar inconstruction and operation to system 300 illustrated previously in FIG.7, except for the size and capacity of the system and the arrangement ofthe filter cartridges. Components of system 500 that are similar indesign and function to corresponding components of system 300 discussedpreviously (although potentially differing in size and design so as toaccommodate the larger size and capacity of system 500, as would beapparent to those of ordinary skill in the art) are given the samefigure labels as in FIG. 7 and are not separately discussed herein.Filtration system 500 in one particular embodiment of the invention,comprises a modified Fluid Solutions Model No. FSRO-600-10VS ReverseOsmosis System (Fluid Solutions, Inc. Lowell, Mass.) having a nominaldesign permeate flow rate of about 30-40 gal./min. The system, asconfigured in the illustrated embodiment, is constructed fromfood/pharmaceutical grade materials. The system may further include, insome embodiments, a variety of additional valves, switches, pressuregauges, transducers, temperature probes, electronic/microprocessor-basedmonitoring/process control hardware and software, etc., in addition tothe particular components illustrated, as would be apparent to those ofordinary skill in the reverse osmosis/nanofiltration arts. System 500,as configured in the illustrated embodiment, includes five filtrationcartridges 502, 504, 506, 508, and 510. Cartridges 502, and 504 arearranged in parallel and are connected in series with cartridges 506,508 and 510, which are connected in series with each other. Parallelcartridges 502 and 504 are fed by inlet manifold 512 connected tocartridges 502 and 504 via lines 514 and 516 respectively. Retentateoutput from cartridges 502 and 504 flows into outlet manifold 518 vialines 520 and 522 respectively, and flows from manifold 518 to cartridge506 via line 524. Retentate output from cartridge 506 is fed tocartridge 508 via line 526, and retentate from cartridge 508 is fed tocartridge 510 via line 528. The concentrated retentate, produced byfinal filtration cartridge 510 flows from the cartridge for collectionor recycle via line 530. Each of the filtration cartridges, 502, 504,506, 508, and 510 as illustrated, includes two FILMTEC® Model No.SW30-8040 spiral-wound filter membrane elements. The filter membraneelements each include about 28 m² of filter membrane area. The maximumoperating pressure for the filter membrane elements is about 1015 psiwith a typical operating pressure of between about 600-900 psi.

As discussed previously, the inventive solvent reduction and de-wateringmethods for forming concentrated consumable extracts, for example coffeeextracts, provide a variety of beneficial features and advantages to theinventive extract producing methods and systems. For example, in someembodiments involving the production of coffee extracts, a de-wateringprocess such as that described above in reference to FIG. 6 can be usedto concentrate and de-water the coffee extracts produced by theinventive extraction methods, previously described, to form even morehighly concentrated coffee extracts, for example containing at leastabout 6% wt. coffee solids, in some embodiments at least about 10% wt.coffee solids, in some embodiments at least about 12% wt. coffee solids,in some embodiments at least about 15% wt. coffee solids, in someembodiments at least about 20% wt. coffee solids, in some embodiments atleast about 25% wt. coffee solids, in some embodiments at least about30% wt. coffee solids and in some embodiments containing at least about40% wt. coffee solids. Furthermore, the highly concentrated extractsproduced by the inventive extraction and de-watering methods describedherein can advantageously retain an effective amount of the varietalflavor and fragrance components of the roasted coffee from which theyare prepared. Such highly concentrated extracts can be advantageouslyused for applications requiring low-water coffee flavoring products. Onesuch application involves the use of the inventive highly concentratedcoffee extracts as a flavoring ingredient for the production of coffeeice cream, where excessive water can lead to detrimental icing andtexture degradation of the final ice cream product. In addition,concentration and de-watering of coffee extracts by the inventiveconcentration methods described herein can advantageously provideconcentrated coffee extract products having a given quantity of coffeesolids contained therein, including an effective amount of varietalflavor and fragrance components, which have a relatively low totalproduct weight and volume. For example, by increasing the concentrationof an extract by a factor of 2, for a given quantity of coffee fragranceand flavor (proportional to the amount of coffee solids present) thevolume of a coffee extract product can similarly be reduced by a factorof 2 and the weight of the product can be reduced by nearly this amount,thus saving substantial shipping and packaging costs, similarly for evenhigher levels of concentration able to be obtained by practicing thecurrent invention, for example increases in concentration by a factor of5, 10, 20, 30, 40, 50, or 60, even greater reduction in shipping,packaging and storage costs can be realized.

Also, as discussed above, the inventive extraction and concentrationmethods allow for the formation of concentrated coffee extracts having avariety of different fragrance and flavor characteristics to be producedby extracting a given charge of roasted coffee. The nature of theinventive extraction processes described herein is that the less waterthat is used for a coffee extraction, the higher will tend to be theconcentration level of coffee solids in the extract produced, but also,the more flavor and extractable coffee solids will tend to be leftbehind in the non-exhaustively extracted grinds remaining in theextractor. Using the inventive concentration method, a first-pass, highconcentration coffee extract can be produced by extracting a freshcharge of roasted coffee with a relatively small quantity of water andset aside as an “extra virgin” coffee concentrate. The roasted coffee inthe extractor may then be subjected to one or more additional extractioncycles utilizing an increased amount of water during the extraction inorder to more exhaustively extract the roasted coffee and improveextraction efficiency. The extracts obtained from these secondary andsubsequent extraction cycles can then be de-watered using the inventiveconcentration methods described above to have, in some embodiments, anoverall coffee solids concentration similar to that of the “extravirgin” concentrate. The “extra virgin” concentrate and the de-wateredconcentrates produced from subsequent extraction cycles can then beblended to form an extract having a balance of relatively sweetflavor/fragrance attributes imparted by the “extra virgin” extract andmore bitter/acidic flavor/fragrance attributes imparted by the extractsproduced by secondary or subsequent extractions of the roasted coffee.These blended extracts often have an overall flavor/fragrance moretypical of beverage quality coffee produced by many prior art coffeebeverage making methods. Such a combined extract may then be used as aflavoring agent, or may be reconstituted by dilution with water to afinal dissolved coffee solid concentration typical of a beveragestrength extract, for example containing between about 1% wt. dissolvedcoffee solids and about 4% wt. coffee solids, to produce a flavorful andwell balanced coffee beverage therefrom. The particular balance betweensweetness and bitterness/acidity can be readily adjusted, as desired,for example by adjusting the relative proportions of “extra virgin”extract and extracts produced by subsequent extraction and concentrationin the blended extract. For embodiments where the overall coffee solidsconcentration of the “extra virgin” extracts and of the extractsproduced by subsequent extraction of the roasted coffee, followed byconcentration of the extract by de-watering, is about the same, where aricher, sweeter extract/beverage is desired, the amount of the “extravirgin” extract added to the blend should be greater than the amount ofextract produced by subsequent extraction and concentration, forembodiments where a tarter, more bitter extract/beverage is desired, theamount of the “extra virgin” extract added to the blend should be lessthan the amount of extract produced by subsequent extraction andconcentration, and for embodiments where a more evenly balancedextract/beverage is desired, the amount of the “extra virgin” extractadded to the blend should be about equal to the amount of extractproduced by subsequent extraction and concentration.

In general, the inventive extraction and de-watering methods provide awide range of flexibility for producing “extra virgin” extracts andother extracts produced by more thorough extraction of a roasted coffee,each having a high level of concentration of dissolved coffee solids,for example at least about 6% wt. dissolved coffee solids, which may becombined in a variety of proportions to produce extracts havingcustomized flavor/fragrance profiles, or which may be sold separately todifferent markets.

Alternatively, in other embodiments, a single charge of roasted coffeecan be exhaustively extracted in a single extraction to produce abeverage strength or lower than beverage strength extract having flavorcharacteristics typical of conventionally brewed coffees, and thisextract can subsequently be de-watered and concentrated as describedabove to produce a concentrated extract having reduced volume andweight, which can subsequently be reconstituted with water to produce acoffee beverage having the same flavor characteristics typical ofconventionally brewed coffees. Because the flavor, quality, andshelf-life of coffee extracts can be reduced by prolonged exposure tooxygen, in preferred embodiments of the invention, the exposure of theextract, during extraction, de-watering, and any subsequent handling,and packaging, to atmospheric air is minimized, for example by utilizinginert gases, such as nitrogen, as blanket/purge gases for contacting theextract during production and processing, as described previously.

The function and advantage of the invention will be more fullyunderstood from the examples below. The following examples are intendedto illustrate the operation of the invention, but not to exemplify thefull scope of the invention.

EXAMPLE 1 One Pass Extraction Without Subsequent De-Watering

The industrial scale extractor described in connection with FIGS. 1-4was used to produce a coffee extract using the methods described in thepreceding sections with the modifications indicated below. Approximately265 lbs. of a blend of Costa Rican, Colombian, and Sumatran coffeebeans, roasted to a medium dark finish, were ground using a Bunn coffeegrinder (HVG, Bunn-o-matic, Springfield, Ill.) on a setting of 4.0. ARotap sieve analysis indicated an 80% retention in Tyler sieves 12, 16,and 18, with the remaining 20% distributed across sieves 20, 30, 40, 45,and the bottom tray.

The vessel was filled with the dry ground coffee forming a bed and thesystem was wetted with hot water, from a supply maintained at 193degrees F. and 90 psig, as described above. Valve 25 on the extractoutlet line 23 was then closed and about 40 gallons of the hot water wasadded to the vessel via inlet line 46 yielding a final vessel pressureof about 90 psig. the vessel was then “burped” to remove excess air aspreviously described and then pressurized to about 120 psig withpressurized air. The coffee was “pressure-treated” at this pressurewithout flow for about 10 min., at which time, valve 25 was opened toallow the extract to flow from the vessel, through a stainless steelheat exchanger (chiller 28) operated to lower the temperature of theexiting extract from about 165 degrees to about 55 degrees F. inapproximately 2 min., and into a collection container. When the pressurein the vessel dropped to about 90 psig, the hot water supply to thevessel was reestablished by opening valve 47 on aqueous solvent inletline 46. An additional 90 gallons of hot water were then passed throughthe bed of coffee before closing valve 47. When no more extract wasobserved flowing from the vessel, pressurized air was supplied to thevessel at 120 psig to purge residual extract from the bed forcollection. The total yield of extract was about 100 gallons from the265 lb of dry coffee.

The extract was judged by taste and smell testing to have exceptionalsweetness with a clear coffee flavor retaining the varietal components,and substantially free of acidic off-flavors. The extract had a Brixreading of about 8.0 (about 6.5% dissolved solubles) and can bereconstituted with about 7 lbs. water per pound of extract to yield acoffee beverage of normal drip brew strength, but with superiorsweetness and flavor.

EXAMPLE 2 Two Pass Extraction with Subsequent De-Watering of theSecond-Pass Extract and Formation of a Blended Coffee Extract

The industrial scale extractor described in connections with FIGS. 1-4was used to produce a coffee extract using the methods described in theprevious section with the modifications indicated below. Approximately200 lbs. of Sumatran coffee beans were roasted and ground as describedabove in Example 1.

The extraction vessel was filled with the dry ground coffee and about 60gallons of a first-pass coffee extract was produced as describedpreviously for Example 1, except that in the present example pressurizednitrogen was utilized in place of the pressurized air in Example 1.Also, the step, in Example 1, of passing additional hot water throughthe bed of coffee performed immediately prior to the purging of residualextract from the bed with gas was omitted in the present example. Thetotal yield of the first-pass extract was about 60 gallons from the 200lbs. of dry coffee. This extract was set aside.

A second-pass extract was prepared, as described above, except using thesame charge of ground coffee used previously for producing thefirst-pass extract, and except that after extract was collected from thevessel immediately subsequent to the pressure treat step and beforepurging residual extract from the bed with nitrogen, an additional of 60gals. of hot water was passed through the bed of coffee in a similarfashion as that described above in Example 1. The total yield ofsecond-pass extract was about 120 gals.

The second-pass extract was then de-watered using the PROSYS Model No.400 Series Reverse Osmosis System (configured with four Model No. 4921SKoch nanofiltration membrane cartridges, arranged in parallel) describedabove in the context of FIG. 6. The system was operated in amulti-pass/recycle mode, as described above, wherein the extract waspumped through the filter elements in a cross-flow fashion, and theconcentrated retentate was recycled to the extract supply container. Thesystem was operated in this fashion until about 60 gals. of aqueoussolvent was collected from the system as permeate. The resultingconcentrated extract was then mixed in equal proportions with thefirst-pass extract produced above to yield a blended, concentratedcoffee extract.

The blended extract was judged by taste and smell testing to have aclear coffee flavor that was well balanced with respect to sweet andbitter/acidic flavor components. The extract also was judged to retainthe varietal components indicative of the Sumatran roasted coffee fromwhich it was prepared. The extract had a Brix reading of about 8.0(about 6.5% wt. dissolved solubles), and can be reconstituted with about7 lbs. water per pound of extract to yield a coffee beverage of normalbrew strength, and with well-balanced coffee flavor including desirablevarietal flavor and fragrance components.

EXAMPLE 3 One Pass Extraction with Subsequent De-Watering to Produce aHighly Concentrated Coffee Extract

An industrial scale extractor similar to that described in connectionwith FIGS. 1-4, except having a dome-shaped upper plate with a single,center-mounted raw material feed line and valve fed by a mechanicalauger feed system. The industrial extractor utilized for the presentexample had an internal capacity of about 62.5 cubic feet, designed toextract about 1300 lbs. of ground, roasted coffee. About 1300 lbs. ofthe ground coffee described in example 2 was fed to the extractor,followed by closure of the valve on the raw material feed line.

The vessel was filled with the dry ground coffee forming a bed and thesystem was wetted with hot water, from a supply maintained at 193degrees F. and 90 psig, as described above, except the first about 250gallons of hot water added to the extractor were added through thebottom screen via line 23 and through tangential lines 42 and 55. At 250gallons, the vent line was closed, and an additional about 50 gallons ofhot water was added to the closed extractor via line 46 and water sprayhead 63, raising the internal pressure of the extractor to about 40-50psig. The coffee was “pressure-treated” at this pressure without flowfor about 30 min., at which time, valve 25 was controllably opened toallow the extract to flow from the vessel at a flow rate of about 6-8gal./min., through a basket filter and stainless steel heat exchanger(chiller 28), which cooled the extract to a temperature of about 50degrees F., and into a collection container. The hot water supply to thevessel was then reestablished at a controlled supply pressure of about40 psig by opening valve 47 on aqueous solvent inlet line 46 and pumpinghot water to the extractor at the above-mentioned pressure and at acontrolled flow rate of about 6-8 gal./min., until an additional about600 gallons of hot water were passed through the bed of coffee, at whichpoint the flow was discontinued and valve 47 was closed. When no moreextract was observed flowing from the vessel, pressurized nitrogen wassupplied to the vessel to purge residual extract (about 100 gallons)from the bed for collection. The total yield of extract was about 1000gallons from the 1300 lbs. of dry coffee.

The 1000 gallons of the above extract was then de-watered using theFluid Solutions Model No. 10037 Reverse Osmosis System (configured with15 FILMTEC Model No. BW30-4040 reverse osmosis membrane cartridges)described above in the context of FIG. 7. The system was operated in amulti-pass/recycle mode, as described above, wherein the extract waspumped through the filter elements in a cross-flow fashion, and theconcentrated retentate was recycled to the extract supply container. Thesystem was operated in this fashion until about 850 gals. of aqueoussolvent was collected from the system as permeate.

The concentrated extract was judged by taste and smell testing to have aclear coffee flavor that was well balanced with respect to sweet andbitter/acidic flavor components. The extract also was judged to retainthe varietal components indicative of the Sumatran roasted coffee fromwhich it was prepared. The extract had a Brix reading of about 30 (about25% wt. dissolved solubles), and can be reconstituted with about 30 lbs.water per pound of extract to yield a coffee beverage of normal brewstrength, and with well-balanced coffee flavor including desirablevarietal flavor and fragrance components.

While the invention has been shown and described above with reference tovarious embodiments and specific examples, it is to be understood thatthe invention is not limited to the embodiments or examples describedand that the teachings of this invention may be practiced by one skilledin the art in various additional ways and for various additionalpurposes. Those skilled in the art would readily appreciate that allparameters and configurations described herein are meant to be exemplaryand that actual parameters and configurations will depend upon thespecific application for which the systems and methods of the presentinvention are used. Those skilled in the art will recognize, or be ableto ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described. The presentinvention is directed to each individual feature, system, or methoddescribed herein. In addition, any combination of two or more suchfeatures, systems, or methods, provided that such features, systems, ormethods are not mutually inconsistent, is included within the scope ofthe present invention.

1-24. (canceled)
 25. An aqueous coffee extract obtained by extraction ofa quantity of roasted coffee, said quantity including at least onechosen variety of roasted coffee, said extract having at least about 15%wt. dissolved coffee solids, and retaining an effective amount of thevarietal flavor and fragrance components characterizing said at leastone chosen variety of roasted coffee from other varieties of roastedcoffee.
 26. The aqueous coffee extract as recited in claim 25, whereinthe extract contains at least about 20% wt. dissolved coffee solids. 27.The aqueous coffee extract as recited in claim 26, wherein the extractcontains at least about 25% wt. dissolved coffee solids.
 28. The aqueouscoffee extract as recited in claim 27, wherein the extract contains atleast about 30% wt. dissolved coffee solids.
 29. The aqueous coffeeextract as recited in claim 28, wherein the extract contains at leastabout 40% wt. dissolved coffee solids.
 30. A method for producing ablended coffee extract, the method comprising: a. extracting a quantityof roasted coffee with a quantity of aqueous solvent to form afirst-pass coffee extract having a concentration of dissolved coffeesolids therein of a first value; b. extracting the same quantity ofroasted coffee previously extracted in step (a) with an additionalquantity of aqueous solvent to form a second-pass coffee extract havinga concentration of dissolved coffee solids therein of a second valueless than first value; c. increasing the concentration of dissolvedcoffee solids in the second-pass coffee extract by removing a quantityof aqueous solvent therefrom; and d. mixing a quantity of the first-passextract with a quantity of the second-pass extract concentrated in step(c) to form a blended extract.
 31. The method as recited in claim 30,wherein in step (c) the concentration of dissolved coffee solids in thesecond-pass coffee extract is increased by removing by filtration aquantity of aqueous solvent therefrom.
 32. The method as recited inclaim 30, wherein in step (d) the quantity of the first-pass extract isgreater than the quantity of the second-pass concentrated in step (c).33. The method as recited in claim 30, wherein in step (d) the quantityof the first-pass extract is less than the quantity of the second-passconcentrated in step (c).
 34. The method as recited in claim 30, whereinin step (d) the quantity of the first-pass extract and the quantity ofthe second-pass concentrated in step (c) are essentially equal.
 35. Themethod as recited in claim 30, wherein in step (c) the concentration ofdissolved coffee solids in the second-pass extract is increased to aboutsaid first value.
 36. The method as recited in claim 35, wherein in step(d) the quantity of the first-pass extract and the quantity of thesecond-pass concentrated in step (c) are essentially equal.
 37. Ablended coffee extract produced according to the method recited in claim30.
 38. The method as recited in claim 30, wherein the blended extracthas a concentration of dissolved coffee solids of at least about 6% wt.39. A blended coffee extract produced according to the method recited inclaim
 38. 40. The method as recited in claim 38, further comprisingafter step (d): e. diluting the blended extract with aqueous solvent sothat the concentration of dissolved coffee solids is between about 1%wt. and about 4% wt.
 41. (canceled)